June 16 EDIT: The cause of this problem has been identified as "Temperature:OFF" in init_d.txt. When this was enabled again, the tiles' temperatures fell to normal levels and haulers picked up the stone.

Bugged save showing an obsidian-farming/magma related pathfinding issue, possibly related to tile temperature not updating correctly, and displaying absurd negative distances to construction materials.

DF version: 0.34.11

Box info: AMD Athlon 7750, 4 Gigs RAM, nVidia GeForce 9400 GT running Arch Linux 3.3.7-1-ARCH x86_64.

Raw modifications:

• [ADOPTS_OWNER] removed from creature_domestic.txt, section CAT
• Ironhand graphics set installed.
• Aging, skill and attribute rust removed from dwarves in creature_standard.txt:
  MAXAGE:150:170
  
  [PHYS_ATT_RATES:STRENGTH:500:NONE:NONE:NONE]
  [PHYS_ATT_RATES:AGILITY:500:NONE:NONE:NONE]
  [PHYS_ATT_RATES:TOUGHNESS:500:NONE:NONE:NONE]
  [PHYS_ATT_RATES:ENDURANCE:500:NONE:NONE:NONE]
  [PHYS_ATT_RATES:DISEASE_RESISTANCE:500:NONE:NONE:NONE]
  [PHYS_ATT_RATES:RECUPERATION:500:NONE:NONE:NONE]
  
  [MENT_ATT_RATES:ANALYTICAL_ABILITY:500:NONE:NONE:NONE]
  [MENT_ATT_RATES:CREATIVITY:500:NONE:NONE:NONE]
  [MENT_ATT_RATES:EMPATHY:500:NONE:NONE:NONE]
  [MENT_ATT_RATES:FOCUS:500:NONE:NONE:NONE]
  [MENT_ATT_RATES:INTUITION:500:NONE:NONE:NONE]
  [MENT_ATT_RATES:KINESTHETIC_SENSE:500:NONE:NONE:NONE]
  [MENT_ATT_RATES:LINGUISTIC_ABILITY:500:NONE:NONE:NONE]
  [MENT_ATT_RATES:MUSICALITY:500:NONE:NONE:NONE]
  [MENT_ATT_RATES:PATIENCE:500:NONE:NONE:NONE]
  [MENT_ATT_RATES:SOCIAL_AWARENESS:500:NONE:NONE:NONE]
  [MENT_ATT_RATES:MEMORY:500:NONE:NONE:NONE]
  [MENT_ATT_RATES:SPATIAL_SENSE:500:NONE:NONE:NONE]
  [MENT_ATT_RATES:WILLPOWER:500:NONE:NONE:NONE]
  
  [SKILL_RATES:100:NONE:NONE:NONE]

Where the buggy area is located: due west (outside the walls) of the above-ground fort there is a 10x10x2 open-air obsidian farm. At the bottom there is a number of mined obsidian boulders that my dwarves refused to haul, despite there being a clear and simple way in and a stockpile accepting obsidian boulders.

Symptoms:

• Whenever an obsidian boulder is created by channeling from the z-level above, a dwarf rushes to the stockpile, picks up a wheelbarrow, and promptly throws a "Urist McHauler cancels Store Item in Stockpile: Item inaccessible" error.
• After this error, trying to build a construction such as a floor or wall in a place with access to the erroneously "inaccessible" obsidian will result in the item list displaying the obsidian atop the item list with some ludicrous negative distance such as -737500001. Restarting the game "clears" this error, but as soon as another obsidian boulder is produced and rejected by a hauler, it will pop up again.
• After mining the obsidian, dwarves will refuse to path over the obsidian floor left where the walls used to be, despite being perfectly able to do so on the obsidian floor one z-level above. If for some reason dwarves fall onto the lower floor, they will not move at all and start to starve until there is a directly adjacent tile which floor is not an obsidian one.

All these symptoms seem to indicate that dwarves avoid the fabricated-obsidian-floored tiles like the plague, despite them being harmless (the dwarf that fell on it survived unscathed). Using DFHack's (which was installed after the bug appeared) "probe" command to analyze the tiles, suspecting something amiss with the new fire-avoidance code, yielded the following results:

• The tiles above the obsidian walls have perfectly normal temperatures: 10015 U and 10022 U respectively. Thus dwarves can path through them normally.
• The local volcano's natural obsidian walls have both "temperature1" and "temperature2" at 10075 U (warm stone). Everything directly adjacent to (but not submerged in) magma has a temperature2 of 10075. However, the manufactured obsidian walls in the pit have a temperature2 of 10075 U despite not being in contact with magma anymore; what's worse, they have a temperature1 of 12000 U, as if they were magma itself.
• After being channeled, the empty space where the obsidian walls used to be has a normal temperature2 of 10022 U, but temperature1 is still 12000 U.

Judging from this, I'm led to believe that the "base-state" temperature of magma-covered tiles is not being properly updated after it is forcibly cooled into obsidian; this, coupled with Toady's new fire-avoidance code in 0.34.11 results in dwarves avoiding said tiles, making obsidian farming practically impossible due to pathfinding issues.

If testers would like to refill the obsidian farm, the controls are the three levers just south of the fort's west entrance, one beside the other: the upper one controls the lava floodgates, the middle one controls the water inlet, and the bottom one controls the water drainage (falls into an aquifer). The pump filling the moat and farm with pressurized magma from the volcano is always on, so have !!FUN!!. Just don't let the magma get to the upper level in the obsidian farm, nor let water in before the lower level is full of magma.